mingw-w64-crt/intrincs/bitscanrev.c - mingw-w64 - Git at Google

 #define __INTRINSIC_ONLYSPECIAL
 #define __INTRINSIC_SPECIAL__BitScanReverse /* Causes code generation in intrin-impl.h */

 #include <intrin.h>
	#define __INTRINSIC_ONLYSPECIAL
	#define __INTRINSIC_SPECIAL__BitScanReverse /* Causes code generation in intrin-impl.h */

	#include <intrin.h>